Pneumatic dispatch system



May 5, 1931.

J. T. COWLEY PNEUMATIC DISPATCH SYSTEM 2 Sheets-Sheet 1 Filed Aug. 7, 1929 Inventor- Jam (#9 T Com/( y May 5, 1931. J. T. COWLEY PNEUMATIC DISPATCH SYSTEM 2 Sheets-Sheet Filed Aug. 7, 1929 Inventor Patented May 5, 1931 UNITED STATES PATENT OFFICE JAMES T. COWLEY, OF SYRACUSE, NEW YORK, ASSIGNOR TO THE LAMSON COMPANY, OF SYRACUSE, NEW YORK, A CORPORATION OF MASSACHUSETTS PNEUMATIC DISPATCH SYSTEM Application filed August 7, 1929. Serial No. 384,095.

This invention relates to an improvement in a pneumatic dispatch system and more particularly in a vacuum pressure system of the minimum flow type comprising two transmission tubes, one connected to a vacuum drum, the other connected to a pressure drum, and both drums being supplied by a single air compressor.

The primary object of this invention is to provide a system of the above type in which the transmission tubes and compressor form a closed circuit, the carriers are impelled by air pressure from the dispatching terminals, and the insertion of a carrier into the circuit initiates a carrier impelling flow by which it is impelled to the desired receiving terminal.

A. further object of this invention is to provide in such a system a single power control which operates vanes in both .transmission tubes, the vane in the vacuum tube being actu ated upon the insertion of a carrier anywhere in the circuit to open such vane and simultaneously to open the vane in the .pressure tube. Other objects of the invention are to providea system in which the necessity of any exhausttube being carried outside the building is avoided, in which longer lines can be run thanwould be possible where either vacuum or pressure alone was used, 30 and in which the air, being confined to a closed circuit makes a quiet operating system, the same air being used over and over again to avoid condensation.

The accompanying drawings illustrate by way of example one embodiment of this invention, and in such drawings,

Fig. 1 is a diagrammatic side elevation on a small scale illustrating this invention;

Fig. 2 is a side elevation on a large scale of a portion of the transmission tubes and the power control;

Fig. 8 is a front elevation of the elements shown in Fig. 2;

Fig. 4 is a sectional view taken along the line 4-4 of Fig. 3; and

Fig. 5 is a sectional view taken along the line 5-5 of Fig. 3. V

. In the selected embodiment is disclosed a central station or desk A from which transmission tubes extend to substations, one such station B being shown as an example. Each of the stations comprises a receiving anddispatching terminal. Transmission tubes .10 and 11 extend between the stations. The tube 10 is connected to a vacuum drum 12 by a line 13 and the tube 11 is connected toa pressure drum 14. by a line 15, such tubes will hereafter be designated'as vacuum and pressure tubes respectively. The drum12 is connected to the vacuum side of an air com pressor 16 and the drum 14 is connected to the pressure side of said compressor.

The terminal 20 at the station E is attached to and connects both tubes 10 and 11. In the terminal 20 is an opening 21 which is normally closed by a spring pressed gate 22. A passage 23 is provided through which air flows freely from the tube 11 to the tube '10. The gate 22 normally, prevents the entry of air into the tube 10 and the escape of air from the tube 11. A chute24 forms an eX- tension of the tube 11 and receives a carrier upon its arrival at the station. A gate 25 is provided in the terminal 20 below the end of the tube 10. This gate, normally closed under spring pressure, may be opened when desired to insert'a carrier.

At the central station is a carrier inlet in the face of the tube 11. This inlet is normally closed by a spring pressed door 31 secured in position by a lock 32. A terminal 33 at the end of the tube 10 has an opening 34; normally closed by a spring pressed gate 35. From the terminal 83 extends a chute 36 which receives the carrier sent through the tube 10 from the substation. The tube 10 is offset at station A and continues beyond the terminal 33 to join the line 18.

The particular terminals, gates, chutes, etc. above described and shown in the drawings are of common construction. They were selected for illustrative purposes and form per se no part of the present invention.

As will be clear from an examination of Fig. 1 in the light of the above description, the transmission tubes, drums and compressor form a closed circuitor line. The compressor 16 runs continuously, thus providing a flow of air through the circuit at all times. Such flow obviously need he at a minimum except when used to impel carriers through the tubes. This regulation of the air flow is obtained by the following mechanism.

Mounted on the vacuum tube 10 is a power control 40 shown in elevation and in section in Figs. 2, 4 and'5. The particular power control .40 selected for illustration in the present case is substantially that shown in my copending application, Serial No. 317,858, filed November 7, 1928, and comprises a plurality of pneumatics which regulate the position of a vane 41 mounted upon a shaft 42. The control 40 normally assumes the position shown in Fig. 5, a by-pass 43 permitting the air to flow past the vane 41. WVhen the necessity for the initiation of a carrier impelling flow of air arises, the pneu matics function in the manner well known to those skilled in the art to rotate the vane 42 into the open position. This position is m aintained as long as the necessity exists. The shaft 42 extends across the tubes 10 and 11 and on it is secured a vane 44. (See Fig. 4.) The vanes 41 and 44 are fixed upon the shaft 42 so that they oscillate in the tubes 10 ans 11 simultaneously. In the vane 44 is an aperture 45 which functions as will be described later in the same manner as the by-pass 43. Slide wind gates 46 and 47 are provided in the tubes 10 and 11 respectively between the drum and the power control for the purpose of-adjusting the air flow through the circuit to any desired volume. The vanes 41 and 44 are normally closed, the by-pass 43 and aperture 45 permitting that a minimum flow of air be maintained through the system in the direction indicated by the arrows on Fig. 1.. The control 40 is adjusted to be very sensitive to the normal condition in which there is no carrier in the line.

"If a carrier is to be sent from the central station A to the substation B, the door 31 is opened and thus any pressure that may exist in the tube 11 is released. The vacuum in the tube 10 is thus increased and the insertionof a carrier into the tube 11 reduces the minimum flow through the circuit. The power control 40 then operates opening the vanes 41 and 44 and allowing a full flow of air through the circuit. The pressure of the air thus admitted to the tube 11 will impel the carrier to the station B. The momentum of the carrier will cause it to open the gate 22 and drop into the chute 24. When the Can rier leaves the line the power control 40 functions in the well known manner to close the vanes 41, 44 and again maintain the minimum flow through the circuit.

When, on the other hand, a carrier is to be returned to the central station from the substation, the gate 25 is opened and the carrier inserted. This similarly reduces the minimum flow in the circuit, causing the power control 40 to open the vanes 41 and 44 and create a full flow of air which impels the can rier to travel through the tube 10 from the substation B to the central station A. Upon arriving at the central station, the momentum of the carrier opens the gate 35 momentarily and then drops into the chute 36.

Since the tubes 10 and 11 form apart of the closed circuit through the compressor, it must follow that should the vanes 41 and 44 close for any reasonwhile a carrier is in either of the transmission tubes, the presence of the carrier will necessarily reduce the minimum flow and build up a higher vacuum in the line causing the power control 40 to act and initiate a carrier impelling fiow.

By providing for the simultaneous opening of the vanes 41 and 44 a balance or correct pressure is maintained in the drums 12 and 14. This of course is necessary in a closed circuit of this nature because the amount of air'circulated through one tube must be equal to the amount circulated through the other at the same time.

While one embodiment only of the invention has been shown and described, I am not limited thereto since other embodiments could be made without departing from the spirit and scope of the invention as set forth in the following claims.

A plurality of carriers may be traveling through the system simultaneously. Due to the circulation through the system the necessity of equalizing the number of carriers in the vacuum and pressure tubes is eliminated and carriers may be inserted into either tube without regard for the condition in the other tube.

I claim:

1. In a pneumatic dispatch system of'the double transmission tube type, an air compressor, means connecting said compressor with both tubes, whereby the tubes and compressor form a closed circuit, and means for maintaining a minimum flow of air through the circuit and for initiating a-carrier impelling flow upon the insertion of a carrier in the line.

2. In a pneumatic dispatch system of the double transmission tube type, an air conipressor, means connecting said compressor with both tubes, whereby the tubes and compressor form a closed circuit, and means for maintaining a minimum flow of air through the circuit and for initiating a carrier impelling flow upon the insertion of a carrier in the line, said last mentioned means including a plurality of vanes and a single means for operating said vanes simultaneously.

3. In a pneumatic dispatch system of the double transmission tube type, an air compres sor, means connecting said compressor with both tubes, wherebythe tubes and'compressor form a closed circuit, and means for maintaining a minimum flow of air through the circuit and for initiating a carrierimpelling flow upon the insertion of a carrier in the line, said last mentioned means including a vane in each transmission tube.

4. In a pneumatic dispatch system of the double transmission tube type, an air compressor, means connecting said compressor with both tubes, whereby the tubes and compressor form a closed circuit, and means for maintaining a minimum flow of air through the circuit and for initiating a carrier impelling flow upon the insertion of a carrier in the line, said last mentioned means including a vane in each transmission tube, and means for operating said vanes simultaneously.

5. In a pneumatic dispatch system of the double transmission tube type, an air compressor, means connecting said compressor with both tubes, whereby the tubes and compressor form a closed circuit, and means for maintaining a minimum fiow of air through the circuit and for initiating a carrier im pelling flow upon the insertion of a carrier in the line, said last mentioned means including a vane in each transmission tube and a power control responsive to the condition in one tube for operating said vanes simultaneously.

6. In a pneumatic dispatch system of the double transmission tube type, an air compressor, means connecting said compressor with both tubes, whereby the tubes and compressor form a closed circuit, and means for maintaining a minimum flow of air through the circuit and for initiating a carrier impelling flow upon the insertion of a carrier in the line, said last mentioned means including a vane in each transmission tube and a power control responsive to the conditions in the vacuum tube for operating said vanes simultaneously.

Signed by me at Boston, Massachusetts, this 2nd day of August, 1929.

JAMES T. COWLEY. 

